1. Field of the Invention
The present invention relates to a video-signal processing device connectable to an electronic endoscope, and more particularly relates to a video-signal processing device that intervenes between an electronic endoscope and peripheral equipment such as a television (TV) monitor, a video tape recorder, a printer, a video-image processing computer, and so on.
2. Description of the Related Art
The described electronic endoscope comprises a flexible conduit and a video processor to which the flexible conduit is detachably joined.
The flexible conduit has an objective lens system provided at the distal end thereof, and a solid state image sensor such as a CCD (charge-coupled device) associated therewith. An object to be photographed is focused, as an optical image, on a light receiving surface of the CCD image sensor by the objective lens system. The optical image is converted into analog image-pixel signals by the CCD image sensor, and the analog image-pixel signals are successively read out of the image sensor by a CCD driver circuit.
Also, the flexible conduit has an optical guide provided therewithin, and the optical guide terminates at a light-emitting end face at the distal end of the flexible conduit. The video processor also includes an optical guide provided therein. When the flexible conduit is joined to the video processor, one end of the optical guide of the video processor is connected to a proximal (base) end of the optical guide of the flexible conduit.
The video processor of the electronic endoscope also has a light source and a collective lens system associated therewith, and light rays emitted from the light source are focused on the other end face of the optical guide of the video processor by the collective lens system. Thus, a front area of the distal end of the flexible conduit is illuminated by the light rays emitted from the light-emitting end face of the optical guide of the flexible conduit.
For reproduction of a photographed image as a color image, for example, an RGB field sequential type color imaging system is introduced in the electronic endoscope. Namely, a rotary RGB color filter is intervened between the light source and the inner end face of the optical guide of the video processor, and the RGB color filter is rotated at a given frequency of rotation. In this manner, an object to be photographed is sequentially illuminated by red light rays, green light rays, and blue light rays. Thus, a red optical image, a green optical image, and a blue optical image are focused on the light receiving surface of the CCD image sensor at given time intervals.
Analog color-image-pixel signals successively read from the CCD image sensor by the CCD driver circuit are fed to the video processor, which processes the analog color-image pixel signals to thereby produce a color video signal. Usually, the video processor of the electronic endoscope is connected to a medical TV monitor designed to ensure electrical security, and a photographed image is reproduced on the medical TV monitor on the basis of the color video signal fed from the video processor thereto.
Also, the electronic endoscope may be connected to a consumer TV monitor at a medical site, for reproduction of a photographed image thereon, but in general the consumer TV monitor is not designed to ensure electrical security. In this case, xe2x80x9celectrical securityxe2x80x9d means both confidentiality and the critical function of electrically insulating a patient from stray current on the signal lines.
On the other hand, it is sometimes desired to connect an electronic endoscope to other peripheral equipments (such as a video tape recorder, a printer, an image-processor and so on) other than a TV monitor. To this end, the video processor of the electronic endoscope is arranged to output at least two kinds of color video signals. However, in this case, of course, the peripheral equipment are not designed to ensure electrical security.
Furthermore, a user may want to connect the electronic endoscope to a peripheral remotely located from the electronic endoscope. For example, at a large hospital of more than two buildings, there may be a case where a color video signal must be fed from the electronic endoscope used in a room of a first building to a peripheral equipment located at a room of another building. In this case, the video signal should be fed as a digital video signal from the electronic endoscope to the peripheral because an analog video signal is susceptible to attenuation.
Nevertheless, the feeding of the digital video signal to the remote peripheral is not expedient because an expensive parallel signal cable having at least plural signal lines corresponding to a bit number of the digital video signal must be laid therebetween.
Therefore, an object of the present invention is to provide a video-signal processing device connectable to an electronic endoscope such that at least one kind of video signal is fed as a serial digital signal from the electronic endoscope to a peripheral equipment such as a TV monitor, a video tape recorder, a printer, an image-processor and so on therethrough, whereby the feeding of the video signal from the electronic endoscope to the peripheral equipment is possible without using an expensive signal cable having a plurality of signal lines.
Another object of the present invention is to provide a video-signal processing device of the above-mentioned type, wherein the feeding of an uncontrollable image in the video signal to the peripheral equipment can be prevented during the connection of the video-signal processing device to the electronic endoscope.
Yet another object of the present invention is to provide a video-signal processing device of the above-mentioned type, wherein the feeding of the image in the video signal to the peripheral equipment can be forcibly stopped, if necessary.
Furthermore, another object of the present invention is to provide a video-signal processing device of the above-mentioned type, wherein the feeding of the image in the video signal to the peripheral equipment is possible in such a manner that the electronic endoscope is electrically insulated from the video-signal processing for electrical security and to protect a patient from stray current on the signal lines.
In accordance with an aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output at least one kind of electric analog video signal, the device comprising: an analog-to-digital converter for converting the electric analog video signal into a parallel electric digital video signal; and a parallel-to-serial converter for converting the parallel electric digital video signal into a serial electric digital video signal, whereby the electric analog video signal outputted from the electronic endoscope is fed outside from the device as the serial electric digital video signal.
The video-signal processing device may further comprise: an electrical-optical converter for converting the serial electric digital video signal into a serial optical digital video signal; a manual switch for forcibly stopping the feeding of the serial electric digital video signal from the device; and a insulation coupler for making it possible to input the electric analog video signal from the electronic endoscope to the device, whereby the electronic endoscope is electrically insulated from the device. The insulation coupler may be a photo-coupler or a transformer coupler.
In accordance with another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output a component-type electric analog color video signal as at least one kind of video signal, the component-type electric analog color video signal being composed of a composite synchronizing signal-component, and at least three kinds of video-signal-components, the device comprising: an analog-to-digital converter for converting the video-signal-components into parallel electric digital video-signal-components; a parallel-to-serial converter for converting the parallel digital video-signal-components into serial digital video-signal-components and for outputting the serial digital video-signal-components in accordance with a series of clock pulses; and a phase-locked loop circuit for coinciding a phase of the clock pulses with a phase of the composite synchronizing signal component of the component-type electric analog color video signal, whereby the serial digital video-signal-components are outputted outside at proper timing from the device.
The video-signal processing device may further comprise: an electrical-optical converter for converting the serial electric digital video-signal-components into serial optical digital video-signal-components; a manual switch for forcibly stopping the outputting of the serial video-signal-components from the device; an insulation coupler for making it possible to input the component-type electric analog color video signal from the electronic endoscope to the device, whereby the electronic endoscope is electrically insulated from the peripheral equipment.
Furthermore, the video-signal processing device may comprise: a phase-lock detector for detecting the coincidence of the phase of the clock pulses with the phase of the composite synchronizing signal; a signal-output stopper for stopping the outputting of the serial digital video-signal-components from the device until the phase-lock detector detects the coincidence of the phase of the clock pulses with the phase of the composite synchronizing signal; and an electrical-optical converter for converting the serial electric digital video-signal-components into serial optical digital video-signal-components.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output a component-type electric analog color video signal as at least one kind of video signal, the component-type electric analog color video signal being composed of a composite synchronizing signal-component, a red video-signal-component, a green video-signal-component, and a blue video-signal-component, the device comprising: a color-conversion analog matrix circuit for producing a luminance signal-component, and two kinds of color-difference signal components on the basis of the read, green, and blue video-signal-components; an analog-to-digital converter for converting each of the luminance signal-component, and the two kinds of color-difference signal components into a parallel electric digital video-signal-components; a parallel-to-serial converter for converting the parallel digital video-signal-components into serial digital video-signal-components and for outputting the serial digital video-signal-components in accordance with a series of clock pulses; and a phase-locked loop circuit for coinciding a phase of the clock pulses with a phase of the composite synchronizing signal component of the component-type electric analog color video signal, whereby the serial digital video-signal-components are outputted outside at proper timing from the device.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output a component-type electric analog color video signal as at least one kind of video signal, the component-type electric analog color video signal being composed of a composite synchronizing signal-component, a red video-signal-component, a green video-signal-component, and a blue video-signal-component, the device comprising: an analog-to-digital converter for converting each of the red, green, and blue video-signal-components into a parallel digital color video-signal-component; a color-conversion digital matrix circuit for producing a parallel digital luminance signal-component, and two kinds of parallel digital color-difference signal-components on the basis of the parallel digital color video-signal components; a parallel-to-serial converter for converting the parallel digital video-signal-components into serial digital video-signal-components and for outputting the serial digital video-signal-components in accordance with a series of clock pulses; and a phase-locked loop circuit for coinciding a phase of the clock pulses with a phase of the composite synchronizing signal component of the component-type electric analog color video signal, whereby the serial digital video-signal-components are out putted outside at proper timing from the device.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output a component-type electric analog color video signal as at least one kind of video signal, the component-type electric analog color video signal being composed of a composite synchronizing signal-component, a luminance signal-component, and two kinds of color-difference signal components, the device comprising: an analog-to-digital converter for converting each of the luminance signal-component, and the two kinds of color-difference signal components into a parallel electric digital video-signal-components; a parallel-to-serial converter for converting the parallel digital video-signal-components into serial digital video-signal-components and for outputting the serial digital video-signal-components in accordance with a series of clock pulses; and a phase-locked loop circuit for coinciding a phase of the clock pulses with a phase of the composite synchronizing signal component of the component-type electric analog color video signal, whereby the serial digital video-signal-components are outputted outside at proper timing from the device.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output at least two kinds of video signals, the device comprising: a switch circuit provided in output-signal lines for the two kinds of video signals; and respective manual switches corresponding the two kinds of video signals for operating the switch circuit in such a manner that an outputting of one of the two kind of video signals from the device is forcibly stopped when turning ON the corresponding manual switch.
In accordance with yet another aspect of the present invention, there is provided a video-signal processing device connectable to an electronic endoscope designed to output at least one kind of video signal, and a plurality of control signals for a video image processing computer, the device comprising: an analog-to-digital converter for converting the electric analog video signal into a parallel electric digital video signal; a parallel-to-serial converter for converting the parallel electric digital video signal into a serial electric digital video signal, whereby the electric analog video signal outputted from the electronic endoscope is fed outside from the device as the serial electric digital video signal; and a processing circuit for processing a command signal, fed from the video-image processing computer to the device, for stopping the feeding of the serial electric digital video signal, whereby the feeding of the serial electric digital video signal is forcibly stopped upon receiving the command signal.